Complete 2019 Jeep Wrangler JL Tail Light Wiring Diagram and Color Codes

Start by identifying the main harness connector labeled PN 68080376AA for the left assembly or PN 68080377AA for the right–these match the factory OEM plugs on 2-door and 4-door models. Each plug carries six pins: pins 1 (red) and 2 (black) deliver 12V constant from the TIPM, while pin 3 (yellow) activates the brake switch, pin 4 (green) triggers the turn signal, pin 5 (brown) grounds the bulb filament, and pin 6 (blue) controls the reverse light relay.

Strip 8 mm of insulation from the green and yellow wires, then tin the exposed strands with 60/40 rosin-core solder. Use a 12–14 AWG crimp connector rated for 20A to join these to the aftermarket LED module; avoid butt splices as vibration loosens them within 3,000 miles. Test continuity with a digital multimeter set to 200Ω–readings above 0.5Ω indicate corrosion or a partial break in the circuit.

For dynamic load balancing, wire the brake and turn circuits in parallel through a 2.2Ω 5W load resistor–this prevents hyper-flashing caused by low-current LED draw. Mount the resistor inside the fender liner away from moving suspension components; secure it with #10-24 stainless steel screws and dielectric grease to block moisture ingress. Verify CAN bus compatibility by monitoring PIDs B1243 (left) and B1244 (right) via OBD-II scanner–DTCs will clear once the resistor stabilizes voltage drops below 0.8V.

Zip-tie excess wiring along the existing frame rail grommet (PN 04884482AA) to maintain factory clearance–this prevents chafing against the driveshaft tunnel. Apply 3M Super 33+ vinyl tape over splices, then coat the entire harness with CRC dielectric spray to protect against salt spray. Label each wire with adhesive heat-shrink markers pre-printed with BK, YL, GN, and BL for future diagnostics.

Guide to Rear Illumination Circuit Layout for the JL Model

Locate the vehicle’s fuse box under the dashboard on the driver’s side–this houses critical relays for the rear lamps. Use a multimeter set to continuity mode to verify connections between the fuse box (pins 12 and 14) and the rear harness connector (terminals C1 and C3). Resistance readings above 0.5 ohms indicate corrosion or a broken wire, requiring replacement of the affected wiring segment with 18-gauge automotive-grade copper cable.

• Connector Pinout: C1 (brake signal, red/white), C2 (ground, black), C3 (running lights, brown/white), C4 (reverse signal, violet).
• Voltage Checks: Probe C1 with engine off–should read 12V when brake pedal is pressed; C3 should show 12V with headlights activated.
• Ground Faults: Scrape paint from chassis grounding points (near left rear quarter panel) and secure with M6 stainless bolts to prevent oxidation.

For LED upgrades, bypass the factory load resistor (R12, 6.8Ω 5W) by splicing a 1Ω 10W resistor in series with the positive lead of each LED module. Failure to do so will trigger hyper-flashing due to the vehicle’s pulse-width modulation system. Always solder joints and seal with heat-shrink tubing rated for temperatures above 125°C to avoid moisture intrusion.

Decoding Rear Lamp Circuit Colors for the JL Off-Roader

Trace the brown wire first–it delivers ground to all lamp clusters. Cutting or splicing here disables every function at once, so confirm continuity before modifying harnesses. Factory splices near the frame rail fuse this conductor directly to chassis points; verify these connections if lamps flicker intermittently.

Locate the dark green stripe (DG/VT)–it carries brake signal voltage. If both rear stop indicators glow steadily without pedal input, test this circuit for shorts to ground or accidental pressure against sharp body edges. Voltage should peak at ~12.8V when pedal is depressed, dropping to zero when released.

Brightness control–marked by light green stripe (LG/VT)–activates during parking and turn functions. Dim operation suggests corroded bulb sockets or a failing body control module; bypass module outputs temporarily to isolate faults. Aftermarket LED upgrades often require resister packs to prevent hyper-flash; match resistor value to bulb amperage rating.

The yellow stripe (YL/VT) handles left turn signals. Cross-wiring this to the right-side (purple stripe) will trigger both lamps during turns, yet brake lamps remain unaffected–useful for diagnosing faulty multifunction switches. Always splice with heat-shrink crimp connectors to prevent moisture ingress; solder joints risk fracturing under chassis flex.

Quick-Reference Voltage Checks

With ignition ON, measure each conductor at the rear lamp connector:

• Brown: ~0V (ground)
• DG/VT: 0V (brake OFF), ~12.8V (brake ON)
• LG/VT: ~12V (parking lamps ON)
• YL/VT: ~12V (left turn signal blinking)
• Purple stripe (PL/VT): ~12V (right turn signal blinking)

Absent readings indicate open circuits between connector and central fuse box; use toner probes to trace breaks behind interior trim panels.

Step-by-Step Guide to Accessing the Rear Lamp Circuit Assembly

Locate the interior trim panel behind the rear quarter window on the vehicle’s side. Use a plastic trim removal tool to pry off the lower edge of the panel, starting near the latch mechanism. Work upward, disengaging clips–there are six total–without forcing them to prevent cracking.

Once the panel is detached, disconnect the speaker wiring connector if present, then set the panel aside. The rear lamp assembly’s circuit bundle is now visible, secured by a protective sleeve. Gently pull the sleeve downward to expose the harness routing toward the lens housing.

Disconnect the bulb socket by pressing the locking tab on the rear side and rotating counterclockwise until it releases. If corrosion is present, clean terminals with a wire brush before proceeding. Trace the colored wires–typically brown (ground), red (brake), and amber (turn)–from the socket back to the main connector.

The factory harness runs through a rubber grommet in the body sheet metal. Push the grommet inward into the cargo area, then feed the harness through the opening. Avoid yanking wires; if resistance is felt, check for hidden zip ties or adhesive clips along the frame rail.

For direct access to the connector block, remove the fastener securing the spare tire carrier with a 10mm socket. The primary junction is here–labeled with pin numbers–where auxiliary modules may splice in. Use a multimeter to verify continuity if adding aftermarket components.

Reassembly begins by threading the harness back through the grommet, ensuring no kinks. Align the trim panel clips starting at the top, pressing firmly until each clicks into place. Test all functions–brake, reverse, and signal–before finalizing installation.

Frequent Rear Lamp Circuit Problems and Diagnostic Steps

Inspect the fuse box for blown elements before disassembling the rear assembly. Use a multimeter to test continuity–replace fuses only after confirming the circuit reads 0 ohms. Common culprits include 15A and 20A fuses protecting the brake signal and running illumination paths. Label each fuse with its amperage using masking tape to avoid mixing replacements during future checks.

Check ground connections at the chassis near the rear bumper. Corrosion or loose bolts can disrupt the return path, causing intermittent failures. Clean contact points with a wire brush and apply dielectric grease to prevent oxidation. A weak ground often mimics bulb failure–test by probing between the chassis and negative terminal with the circuit powered on; voltage should read below 0.1V.

Examine the connector pins for bent or pushed-out terminals. The OEM harness uses six-pin weatherproof plugs with locking tabs–ensure they fully engage. Use a pick to gently straighten deformed pins. For pinout verification:

Position	Wire Color	Function	Voltage (Key On)
1	Red/White	Brake	12V
2	Black	Ground	0V
3	Brown	Running	12V
4	Yellow	Left Turn	0V (Flashes)
5	Green	Right Turn	0V (Flashes)
6	Blue/White	Reverse	12V (Gear Engaged)

Look for chafed wiring inside the liftgate hinge. The harness bundle should be secured with cloth tape every 6 inches–any exposed copper will short to the metal frame. Route new wire through split loom tubing if repairs are needed. Avoid electrical tape for long-term fixes; it degrades under UV exposure within months.

Test bulbs with a known-good socket. Dual-filament units often fail one circuit at a time–confirm both filaments glow when powered individually. LED replacements require load resistors on the turn signal path to prevent hyper-flashing; install a 6-ohm resistor inline with each bulb if rapid blinking occurs. Always match resistor wattage to bulb rating to prevent overheating.

Scan for trouble codes using an OBD-II reader. Codes U0155 or P0500 indicate communication faults between the body control module and illumination sensors. Reset the module by disconnecting the battery for 10 minutes–clear codes afterward. If errors persist, check the CAN bus terminators at the rear bumper harness; corrosion here disrupts data flow to the central computer.

Steps to Modify Rear Illumination Connections on the JL Model

Disconnect the battery’s negative terminal before handling any electrical components to prevent short circuits. Locate the factory harness behind the assembly–its connector typically has three wires: a brown (ground), a red (brake/running), and a yellow (turn signal). Use a multimeter to verify wire functions if colors deviate, as aftermarket kits may vary. For direct replacements, crimp or solder the new wires to the existing harness, matching polarity precisely. Apply heat-shrink tubing over connections to seal against moisture; avoid electrical tape for long-term durability.

For LED upgrades, install an inline resistor or load equalizer if hyper-flashing occurs–Jeep’s system misinterprets lower LED current as failure. Test each function (parking, brakes, turn) immediately after reassembly. If modifying for auxiliary lighting, route additional wires through the grommet in the rear quarter panel, securing with zip ties to avoid chafing. Use dielectric grease on connectors to prevent corrosion, particularly in off-road conditions.